Public Health Assessment and Wellness

Health
5 things to know about Legionnaires' disease

It will take a couple of weeks before water-testing results are back from the Foothill Ranch community pool and spa used by two adults who were hospitalized with Legionnaires' disease.

No new illnesses have been reported since the pool closure May 12. The two cases are among 28 county-wide this year, according to the Orange County Health Care Agency.

Here are five things to know about the illness and its causes:

What is Legionnaires' disease?

It is a severe type of pneumonia caused by a bacterium called Legionella. The bacterium is named after a 1976 outbreak, during which 34 people who attended a Philadelphia convention of the American Legion died after exposure to a contaminated air conditioning system at their hotel.

How is it transmitted?

It usually results from inhaling microscopic water droplets in mist or vapor. Legionella living in fresh water rarely cause infections. But indoors, the bacteria can multiply in water systems ranging from hot tubs and air conditioners to mist sprayers in grocery store produce aisles, according to the Mayo Clinic.

It is not spread through person-to-person contact.

How common is it?

In the last five years, Orange County has seen anywhere from 16 to 53 cases annually, said Health Care Agency spokeswoman Jessica Good. She said the cause of illness is known in very few of the cases.

Nationwide, the Centers for Disease Control and Prevention says up to 18,000 people are hospitalized each year with the illness.

What are the symptoms?

Symptoms usually begin two to 10 days after exposure, according to the CDC. They include: cough, shortness of breath, fever, muscle aches and headaches. The illness is treatable with antibiotics but often requires hospitalization.

Those most at risk for illness are people over 50, smokers, and those who have chronic lung disease or a weakened immune system.

What type of water maintenance is needed to prevent transmission?

According to the CDC, the warm water found in hot tubs can become contaminated if it is not sufficiently cleaned or disinfected. The agency recommends that users ask these questions:

What was the most recent health inspection score for the hot tub?

Are disinfectant and pH levels checked at least twice per day? Are disinfectant and pH levels checked more often when the hot tub is being used by a lot of people?

Are the following maintenance activities performed regularly: removal of the slime or biofilm layer by cleaning; replacement of the water filter according to manufacturer's recommendations; replacement of spa water?